Koden CVS-841 - Setting the STC; Setting the STC Amplitude; Setting the STC Depth

CVS-841/851 Chapter 5
Basic Operation
5.2.6 Setting the STC
The STC (Sensitivity Time Control) is used to reduce the receiver gain in proportion to time, which is
useful to eliminate nearby unwanted echoes like plankton, jelly fish, etc. There are two STC controls
provided, STC Depth and STC Amplitude. Refer to the following descriptions of these controls before
attempting the operation.
5.2.6.1 Setting the STC Depth
In this mode, you are reducing the receiver sensitivity against the depth in a time proportional law with
the STC amplitude fixed. This mode is useful in deep sea fishing to locate a school of fish and the
species.
STC Amplitude
Figure 5.8 Adjusting the STC depth
STC
Strength
A
C
B
Max
Max
Operational notes for STC amplitude adjustment
(1) STC law A: STC is not enough, causing noise and unwanted residual weak echoes in shallow
and mid depth zone to be shown.
(2) STC law B: STC is appropriate, causing unwanted echoes to be perfectly reduced while schools
of fish are shown without degradation.
(3) STC law C: STC is too much, causing the echoes from fish school to be reduced too much.
5.2.6.2 Setting the STC Amplitude
In this mode, you are reducing the receiver sensitivity in a time proportional law with the STC depth
fixed. This mode is useful in a shallow water fishing to gain better view of a school of fish near the sea
surface.
A
B C
STC Amplitude
STC
Depth
Max
A
B
C
Max
Figure 5.9 Adjusting the STC amplitude
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